This invention relates to a blood sampling unit which will permit its utilization without the preassembly of parts. More particularly, it relates to an arterial blood sampling device with a sealing and stopper piercing element which will allow arterial blood pressure to move it along the inside of a syringe barrel and permit blood to collect in a sealed chamber created thereby. The invention also relates to an arterial blood sampling unit which contains an anticoagulant which is activated into the sampling unit prior to its use.
Blood sampling is commonly effected by the utilization of an evacuated container and in conjunction with a piercing apparatus such as described in U.S. Pat. No. 3,886,930. A syringe-type unit for blood collection is described in U.S. Pat. No. 3,753,423. The utilization of a syringe with a preassembled vial is taught in U.S. Pat. No. 3,378,008. As indicated, all of the prior art devices either utilize an evacuated container or the manipulation of a syringe in order to effect a vacuum so as to collect blood into a syringe chamber or vial. In those instances where an evacuated container or a syringe is utilized, it must first be treated with an anticoagulant so that blood clots do not occur when the blood is being collected.
Nowhere in the prior art is there available a blood sampling unit which is preassembled in such a manner that the operator does not have to preassemble components of the unit nor that precautions must be taken to assure that a vacuum is contained in a container prior to its use. Neither is there available a preassembled unit which contains an anticoagulant wherein the device can be easily treated with an anticoagulant material nor a unit which is self-actuating in that the arterial blood will actuate a sealing element so as to fill a container or vial without the presence of air.
It is an advantage of the present invention to afford a novel blood sampling unit which is preassembled and can be activated with a minimum number of manipulative steps. Other advantages are a blood sampling unit which contains an anticoagulant material and a combined stopper and sealing element which is actuated by blood pressure so as to afford a chamber in the blood collecting container, a blood sampling unit which obviates an evacuated container yet does not require the manipulation of a syringe plunger to withdraw blood from a blood vessel, a blood sampling unit which is easy to manufacture and assemble as well as a unit which is fabricated in such a way that it is disposable.